Compass pencil clamp



Feb. 13, 1962 A. AUGUSTIN 3,020,641

COMPASS PENCIL CLAMP Filed Feb. 17, 1960 2 Sheets-Sheet 1 INVENTOR.

AAA-X AUGUST/IV Feb. 13, 1962 A. AUGUSTIN 3,020,641

COMPASS PENCIL CLAMP Filed Feb. 17, 1960 2 Sheets-Sheet 2 INVENTOR. AZEX AUGUST/N AWMM ATTORA/AKS ilniteri rates Patent 9 3,020,641 COMPASS PENCIL CLAMP Aiex Augustin, Sparrowbush, N .Y. Filed Feb. 17, 1960, Ser. No.-9,243 3 Claims. (Cl. 33-27) The present invention relates generally to compasses and specifically to an improved pencil clamp for use in conjunction with a pencil compass.

The use of a compass to draw a circle or a portion of an arc is well known in the art and a large variety of differing compasses have been produced. The present invention is concerned specifically with that type of compass which employs the use of a pencil to describe the are or circle produced. The pencil compass is a relatively inexpensive item and is generally designed for mass production manufacture and low selling price. A persistent problem which has existed in the manufacture of pencil compasses has been the difficulty in producing a mechanism which will easily and accurately clamp a pencil within the compass and at the same time, be relatively inexpensive to manufacture. Included within the disadvantages of the prior art clamps for pencil compasses has been the general failure to solve the problems connected with the requirement for easy removal of the pencil for sharpening, the accurate adjustment of the pencil relative to the compass as the pencil point becomes worn and a clamping of a pencil within the pencil compass Without damaging the pencil.

Generally, it is an object of the present invention to provide a pencil clamp for use in a pencil compass which eliminates the disadvantages of the prior art pencil clamps as described above. Specifically it is an object of the present invention to provide a pencil clamp which will firmly secure a pencil to one leg of a compass and which will allow for easy positioning of the pencil.

A further object of the present invention is to provide a pencil clamp which will not mar the surface of a pencil contained therein.

It is still a further object of the present invention to provide a pencil clamp which is relatively easy to manufacture in mass production techniques and which effectively clamps a pencil such that its position within the clamp may be adjusted.

In accordance with one illustrative embodiment of the present invention there is provided a conventional pencil compass which incorporates, as anintegral part of one of its legs, an improved pencil clamp. The pencil clamp comprises a cylindrical band of flexible material having a longitudinal slit which extends the length of the cylindrical band. Two ears are provided which protrude outwardly from the cylindrical band at points on opposite sides of the longitudinal slit. A rotatable clamping lever, having camming walls which define a kidney opening therein, is engaged about the protruding cars such that upon rotation of the clamping lever the ears are drawn together, thus decreasing the Width of the longitudinal slit. As the width of the slit is decreased, the internal diameter of the cylindrical band is likewise decreased, thereby providing a clamping action for a pencil contained within the clamp.

As a second illustrative embodiment of the present invention there is provided a similar pencil compass having a similar cylindrical band having a longitudinal slit therein and incorporating similar protruding ears. In this second illustrative embodiment a slide having converging camming walls is positioned about the protruding cars such that relative movement between the slide and the ears is effective to draw the ears together. This action is effective to decrease the internal diameter of the cylindrical band and, thereby, clamp a pencil within the clamp.

The above brief description as well as further objects features and advantages of the present invention will be best appreciated by reference to the following detailed description of a presently preferred embodiment, when taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a side elevational view of a pencil compass incorporating a pencil holder according to a first embodiment of the present invention;

FIG. 2 is an enlarged fragmentary view of the pencil clamp of the compass shown in FIG. 1;

FIG. 3 is an elevational view of the rotatable clamp and the camming walls of the device shown in FIG.'2;

FIG. 4 is a sectional view taken along the lines 44 in FIG. 2 and looking in the direction of the arrows;

FIG. 5 is a sectional view taken along the lines 55 in FIG. 2 and looking in the direction of the arrows;

FIG. 6 is a side elevational view of a pencil compass incorporating a pencil clamp according to a second embodiment of the present invention;

FIG. 7 is an enlarged fragmentary view of the pencil clamp shown in FIG. 6, the clamp being illustrated in its clamping position; I FIG. 8 is a view similar to FIG. 7 with the clamp being illustrated in its opened position; and,

FIG. 9 is a sectional view taken along the lines 9-9 in FIG. 7 and looking in the direction of the arrows. Referring now specifically to the drawings, there is shown in FIG. 1 a pencil compass, generally labelled by the numeral 10, incorporating a pencil holder or clamp generally designated by the numeral 12. The pencil compass 10 is of conventional structure and is comprised of two legs l t-and 16, which are pivotally joined at their upper ends by the pivot rivet 18. Frictional clamping forces are provided between the two legs 14, 16 by the pivot rivet 18, spring washers 20, and-the centerplate 2 2 which has a center post 24. The pivot rivet 18, the spring washer 20, the center'plate 22 and the legs 14, 16 are assembled in a manner which is well known to those skilled in the art, such that the'center post 24 always bisects the angle between the legs 14, 16. The'leg 14 has attached to its lower portion a pointed member 26about which the compass 10 is pivoted when in use. The other leg 16 has anarcnate extension 28 which extends inwardly towards the leg 14 and extends beyond the leg 14. The arcuate extension 28 serves as an index of the radius of the are described by the compass. A scale 30, inscribed on the extension 28 coats with the index marker 32 on the leg 14 to'provide this reading. In use, the operator of the pencil compass 10 places the pointed member 26 at the center of an arc to be formed and, with thepe'ncil P which is supported in the holder 12, he describes an are about the point of member 26. p 7 I,

The pencil holder, best seen in FIGS. 2 and 4, consists of a cylindrical band 34 which has an internal diameter approximately equal to the diameter of the pencil P. The

band34 has an opening or slit 36 which runs the length ofthe band 34 and has two juxtaposedside edges 38, 40 which define the width of the opening 36. The cylindrical band 34 is constructed of a flexible material, such that the widthof the slit 36 maybe elastically varied. It will be appreciated that upon a decrease of the wdth ofthe slit 36 by a movement of the side edg'es'38, 40 towards each other, theinternal diameter of the cylindrical band 34 will be decreased thereby positively gripping a pencil P disposed therein. Clamping mechanisms 42 are provided to achieve this clamping action. A pair of clamping cars 44, 46 extend outwardly from the cylindrical band 34 at'opposing points along the side edges 38, 40, respectively, of the opening or slit 36. The ears 44, 46 are bent 3 away from the opening 36 and are partially folded back against the band 34.

A rotatable clamping lever 48, having a kidney shaped opening therein, is operative to engage the ears 44, 46 for a clamping action. The kidney shape opening 50, as is best seen in FIG. 3, is defined by the camming walls 52 which assume a kidney-like shape. The opening 50 has a dimension b, generally parallel to the length of the clamping lever 48, which is greater than the corresponding transverse direction a. Referring once again to FIG. 2, the ears 44, 46 are disposed within the opening 50 and engage the camming walls 52 in an abutting relationship. When the clamping lever 48 is oriented with respect to the cars 44, 46 as is shown in the solid line position labeled A in FIG. 2, the cars 44, 46 will engage the camming walls 52 across the shorter dimension a. Thus the opening or slit 36 will be decreased in width and the effective internal diameter of the cylindrical band 34 will be reduced to clamp a pencil therein. When the rotatable clamping lever 48 is rotated about its opening 50 in a clockwise direction, as viewed in FIG. 2, to the first dotted line position generally designated B, the cars 44, 46 will engage the camming walls 52 across the greater dimension b. Thus, the opening 36 will he at its maximum width and, therefore, the effective diameter of the cylindrical band 34 will be at its maximum dimension thus releasing a pencil P disposed therein. The clamping lever 48 is provided with a finger tab 54 disposed at the outward extremity of the lever 48 and at right angles thereto thus providing convenient means for the rotation of the clamping lever 48.

The opening 50 in the clamping lever 48 is provided with a positioning extension 56 which is effective to hold the clamping lever 48 in its clamping position relative to the ears 44, 46. As will be appreciated by an examination of FIGS. 2 and 3, the extension 56 produces a bump in the camming wall 52 over which the ear 46 must pass before the clamping lever 48 may be moved from the clamping position A to the unclamped position B. Thus, it is necessary for the cars 44, 46 to be further drawn together by the clamping lever 48 before the lever 48 may be moved out of its clamping position. By this means a locking action is achieved which prevents accidental unclamping of the pencil P. It will be further appreciated that the clamping lever 48 may be rotated about the ears 44, 46 only in a clockwise direction as viewed in FIG. 2. At the end of the extension 56 a point 58 is formed in the camming wall 52, which is engaged against the inside surface of the car 46 at the fold between the car 46 and the cylindrical band 34. If an attempt is made to rotate the lever 48 in a counterclockwise direction from its clamping position A, the point 58 will not slide relative to the ear 46 and the counterclockwise rotation of the clamping lever 48 will be thereby restrained.

Reference will now be made to FIGS. 6 through 9 for a description of a second clamping device according to the present invention. A pencil compass 100, similar to the compass 10 shown in FIG. 1, is provided with a pencil holder or clamp 112, legs 114, 116, a pivot rivet 118, spring washers 120, a centering plate 122, a center post 124, a pointed member 126 disposed at the lower end of leg 114 and an arcuate extension 128 of leg 116 having a scale 130 thereon to indicate the radius of the are which the compass will describe.

The pencil holding clamp 112 is integral with the leg 116 and is located at the lower extremity thereof. A flexible cylindrical band 134, formed in a manner similar to the device pictured in FIG. 2 above, has a longitudinal opening 136 having parallel side edges 138, 140 which define the width of the slit 136. It will be appreciated that the width of the slit 136 governs the dimension of the internal diameter of the band 134 such that when the slit 136 is narrowed the diameter of the band decreases thus providing effective clamping means for a pencil P. Clamping mechanisms 142 are provided to accomplish this result. The clamping mechanisms 142 consist of a pair of cars 144, 146 which extend outwardly from the cylindrical band 134 at opposing points along the edges 138, respectively of the opening 136. The cars 144 146 are bent away from the opening 136 and are folded partially back against the cylindrical band 134. A slide 148 is provided with converging camming walls 152, 154 which define an opening 150 contained therein. As may be seen in FIGS. 7 and 8, the converging camming walls 152, 154 are closer together at the upper end of the slide 148 than at the lower end thereof. The clamping ears 144, 146 are contained within the opening 150 and are engaged in abutting relationship with the respective camming walls 152, 154. It will thus be appreciated that when the slide 148 is moved downwardly relatively to the ears 144, 146 the opening 136 will be narrowed by the camming action of the camming walls 152, 154 on the ears 144, 146 respectively, and thus the internal diameier of the cylindrical band 134 will be reduced into a clamping position. The clamp 112 is pictured in its clamping position in FIG. 7. A finger tab 156 is provided on the upper end of the slide 148 to facilitate the movement of the slide 148 relative to the ears 144, 146. When the slide 148 is moved from the position shown in FIG. 7 to the position shown in FIG. 8, i.e., moved upwardly relative to the ears 144, 146, the ears 144, 146 will be engaged in the lower portion of the slide 148 wherein the camming walls 152, 1'54 are spaced relatively far from each other. Thus, the clamping ears 144, 146 will be allowed to spread apart and thus increase the diameter of the cylindrical band 134. When a pencil P has been placed in the desired position relative to the holder or clamp 112 as seen in FIG. 8, the operator moves the slide 148 by means of the finger tab 156 downwardly relative to the ears 144, 146 thus camming them towards each other by the action of the camming walls 152, 154.

It will be appreciated that two embodiments of the present invention have been disclosed which provide easily operative and effective clamping means to retain a pencil within a pencil compass. A simple camming device is utilized to decrease the width of an opening in a cylindrical band, the cylindrical band being approximately the diameter of a pencil. When the sides of the opening are drawn together the pencil is clamped within the cylindrical band. Positioning of the pencil with respect to the band is relatively simple and the device itself is both dependable and relatively inexpensive to manufacture.

A latitude of modification, substitution and change is intended in the foregoing disclosure and in some instances some features of the invention will be used without a use of other corresponding features. Accordingly, the claims herein should be construed broadly and in a manner consistent with the spirit and scope of the invention.

What I claim is:

l. A pencil holder for use with a pencil compass having two legs comprising a flexible cylindrical band integral with one of said legs of said compass, said cylindrical band having a longitudinal opening having parallel edges extending the length of said band, two ears protruding outwardly from said cylindrical band and extending from said edges at points on opposite sides of said longitudinal opening, and releasable clamping means comprising a rotatable clamping lever having camming walls defining a kidney-shaped opening therein through which said ears protrude, said ears being engaged by said camming walls, said opening having a positioning means to maintain said clamping lever in a clamping position, said clamping lever being effective to draw said ears and said edges of said longitudinal opening together or to allow them to spread apart upon a rotation of said clamping lever with respect to said ears.

2. A pencil holder for use with a pencil compass having two legs comprising a flexible cylindrical band on one of said legs of said compass, said cylindrical band having a longitudinal opening having parallel edges extending the length of said band, two cars protruding outwardly from said cylindrical band and extending from said edges at points on opposite sides of said longitudinal opening, and a rotatable clamping lever having camrning walls defining an opening therein through which said ears protrude, said ears being engaged by said camming walls, said opening being of greater length in one direction than in a transverse direction and said camrning walls having a positioning extension which is effective to maintain said clamping lever in a clamping position, said clamping lever being effective to draw said ears together or to allow them to spread apart upon a rotation of said clamping lever with respect to said ears.

3. In a compass having two legs connected at a pivot, a self-centering plate between said legs at said pivot, and a pointed member at the end of one of said legs, a pencil holder including a cylindrical band on the other one of said legs, said pencil holder having a longitudinal opening having parallel sides extending the length of said band, two cars integrally formed with and projecting outwardly from said cylindrical band on opposite sides of said longitudinal opening, and releasable camming means engaging said ears to draw said ears toward each other thereby reducing the diameter of said cylindrical band to clamp a pencil therein, said camming means including a rotatable clamping lever having camming walls which define an opening therein through which said ears protrude, said opening being of greater length in one direction than in a transverse direction, and positioning means on said camming walls of said rotatable clamping lever which is eifective to maintain said clamping lever in a clamping position.

References Cited in the file of this patent UNITED STATES PATENTS 

